Synergistine derivatives, their preparation and pharmaceutical compositions containing them

ABSTRACT

The invention provides novel synergistine derivatives of the formula: ##STR1## in which Y=H or N(CH 3 ) 2  : and R 1  =H and R 2  =OH or alkyl optionally substituted by COOH, alkoxycarbonyl or OH or by alkylamino or dialkylamino the alkyl radicals of which can form a heterocycle, or R 2  =cycloalkyl (of 3 to 7 carbons) or a heterocycle chosen from azetidine, pyrrolidine, piperidine or azepine (optionally substituted on the nitrogen by alkyl), or R 1  =formyl or alkylcarbonyl and R 2  =alkyl substituted by COOH or by alkylamino or dialkylamino the alkyl radicals of which can form a heterocycle, or R 2  is a heterocycle as defined above, or R 1  and R 2 , which are identical or different, represent alkyl optionally substituted by COOH, alkoxycarbonyl, OH, alkylamino, or dialkylamino of which the alkyl radicals can form a heterocycle, or R 1  and R 2  form an azetidine, pyrrolidine, piperidine, morpholine or piperazine ring (optionally substituted by alkyl), all the alkyls having 1 to 5 carbon atoms. These compounds are useful as antibacterial agents.

Pristinamycin and virginiamycin are known synergistine compounds: J.Preud'homme et al., Bull., Soc. Chim. Fr. 2, 585-91 (1968).

The present invention provides new synergistine derivatives of theformula: ##STR2## in which Y is hydrogen or dimethylamino; and R₁ ishydrogen and R₂ is hydroxyl, alkyl, alkyl substituted (by carboxyl,alkoxycarbonyl, hydroxyl, alkylamino, or dialkylamino, in which thealkyls can form, with the nitrogen atom to which they are attached, a4-membered to 7-membered heterocycle chosen from azetidinyl,pyrrolidinyl, piperidinyl, piperazinyl, N-alkylpiperazinyl, andazepinyl), or alternatively R₂ is cycloalkyl of 3 to 7 carbon atoms or asaturated 4-membered to 7-membered heterocycle chosen from azetidinyl,pyrrolidinyl, piperidinyl and azepinyl, these heterocycles beingunsubstituted or substituted on the nitrogen atom by alkyl or R₁ isformyl or alkylcarbonyl and R₂ is alkyl substituted by carboxyl,alkylamino or dialkylamino in which the alkyls can form, with thenitrogen atom to which they are attached, a 4-membered to 7-memberedheterocycle chosen from azetidinyl, pyrrolidinyl, piperidinyl,piperazinyl, N-alkylpiperazinyl and azepinyl, or R₂ represents asaturated 4-membered to 7-membered heterocycle chosen from azetidinyl,pyrrolidinyl, piperidinyl and azepinyl, these heterocycles beingunsubstituted or substituted on the nitrogen atom by alkyl, or R₁ andR₂, which are identical or different, are each alkyl or alkylsubstituted by carboxyl, alkoxycarbonyl, hydroxyl, alkylamino ordialkylamino in which the alkyls can form, with the nitrogen atom towhich they are attached, a 4-membered to 7-membered heterocycle chosenfrom azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl,N-alkylpiperazinyl and azepinyl, or R₁ and R₂ together form, with thenitrogen atom to which they are bonded, a 4-membered to 7-memberedheterocycle chosen from azetidinyl, pyrrolidinyl, piperidinyl,morpholinyl and piperazinyl unsubstituted or substituted by alkyl; allthe aforesaid alkyl radicals and alkyl portions of radicals containing 1to 5 carbon atoms each in a linear or branched chain; and theirpharmaceutically acceptable salts, especially acid addition salts.

According to a feature of the invention, the compounds of the formula(I), with the exception of those in which R₁ is formyl or alkylcarbonyl,are prepared by reacting an amine of the formula: ##STR3## in which R₁and R₂ are as defined above, except that they cannot represent formyl oralkylcarbonyl, with a synergistine of the formula: ##STR4## in which Yis hydrogen (virginiamycin S) or dimethylamino (pristinamycin I_(A)), inthe presence of an alkali metal cyanoborohydride.

The reaction is generally carried out with an excess of amine of thegeneral formula (II), in the presence of an alkali metalcyanoborohydride such as sodium cyanoborohydride, in an organic solvent,such as an alcohol, in which hydrogen chloride has been dissolved(methanol containing hydrogen chloride or ethanol containing hydrogenchloride), at a temperature of between 0° C. and the reflux temperatureof the reaction mixture, preferably at a temperature of the order of 20°C.

The reaction can advantageously be carried out in the presence of adrying agent such as molecular sieves.

It is understood that if R₁ and/or R₂ in the general formula (II)represent a radical containing a secondary amine group, this must beprotected before reacting the product of the general formula (II) withthe product of the general formula (III).

The protection and the freeing of the amine group are carried out by anyknown method which does not affect the rest of the molecule.

It is particularly advantageous to use the trifluoroacetyl radical asthe blocking radical; this can then be removed using an aqueous solutionof an alkali metal bicarbonate such as sodium bicarbonate or potassiumbicarbonate.

According to the invention, the products of the general formula (I) inwhich R₁ represents a formyl or alkylcarbonyl radical and R₂ representsan alkyl radical substituted by a carboxyl radical or by an alkylaminoor dialkylamino radical of which the alkyl radicals optionally form,with the nitrogen atom to which they are attached, a 4-membered to7-membered heterocycle chosen from azetidinyl, pyrrolidinyl,piperidinyl, piperazinyl, N-alkylpiperazinyl or azepinyl, or representsa saturated 4-membered to 7-membered heterocycle chosen from theazetidine, pyrrolidine, piperidine and azepine rings, it being possiblefor these heterocycles to be substituted on the nitrogen atom by analkyl radical, and Y is defined as above, can be prepared by reacting aproduct of the general formula:

    R--CO--X                                                   (IV)

in which R represents a hydrogen atom or an alkyl radical and Xrepresents a halogen atom or an alkylcarbonyloxy radical, with a productof the general formula: ##STR5## in which Y is defined as above and R'₂has the corresponding definition of R₂ given above.

The reaction is generally carried out in an organic solvent such aspyridine, a chlorinated solvent (methylene chloride) or an ether(tetrahydrofuran), in the presence of an acid acceptor such as anorganic base like triethylamine, or an inorganic base such as an alkalimetal carbonate or bicarbonate like sodium bicarbonate, at a temperatureof between 0° C. and 80° C.

Those skilled in the art will understand that if R'₂ represents aradical containing a secondary amine group, the said group must beprotected before reacting the product of the general formula (IV) withthe product of the general formula (V). This can be effected using anycustomary blocking means employed for protecting an amine group andcapable of being removed thereafter, without affecting the rest of themolecule. The reaction is carried out in particular under the conditionsdescribed above.

The products of the general formula (I) in which R₁ represents ahydrogen atom, R₂ represents a hydroxyl radical and Y is defined asabove can also be prepared by reducing the products of the generalformula: ##STR6## in which Y is defined as above.

The reduction can be carried out by any known method for reducing anoxime to a hydroxylamine without affecting the rest of the molecule. Itis particularly advantageous to carry out this reduction by means of analkali metal cyanoborohydride such as sodium cyanoborohydride, inmethanol solution, in the presence of hydrogen chloride.

The amines of the general formula (II) can be obtained by analogy withthe method described in J. Amer. Chem. Soc., 54, 1499 (1932) and J.Amer. Chem. Soc., 54, 3441 (1932) (it being understood that if R₁ and/orR₂ contain an alkylamino radical, this is protected beforehand by anyknown method which does not affect the rest of the molecule), oralternatively if R₁ is a hydrogen atom and R₂ is a saturated 4-memberedto 7-membered heterocyclyl radical, the amines of the general formula(II) can be prepared by applying the methods described by E. F. Elslageret al., J. Med. Chem., 17, 99 (1974) and L. M. Werbel et al., J. Het.Chem., 10, 363 (1973).

The products of the general formula (VI) can be prepared by reactinghydroxylamine with a product of the general formula (III) according tothe known methods.

The new products of the general formula (I) can be purified by thecustomary known methods such as crystallization, chromatography orsuccessive extractions in an acidic or basic medium. For those skilledin the art who are familiar with the sensitivity of synergistines in analkaline medium, it is obvious that the term "basic medium" isunderstood as meaning a medium which is just sufficiently alkaline tofree the parent substance from its acid addition salt, i.e. a mediumwhose pH does not exceed 7.5 to 8.

The new products of the general formula (I) in which the various symbolsare defined as above, with the exception of those in the molecule ofwhich R₁ represents a formyl or alkylcarbonyl radical and R₂ representsan alkyl radical substituted by a carboxyl radical, can be converted toaddition salts with acids by reaction with an acid in an organic solventsuch as an alcohol, a ketone, an ester or a chlorinated solvent. Thesalts precipitates, if appropriate after concentration of its solution;it is separated off by filtration or decantation. The acid additionsalts can also be obtained in the form of aqueous solutions by theaddition of an aqueous solution of the corresponding acid to the productof the general formula (I) such as it has just been defined.

The new products of the general formula (I) in which the radicals R₁and/or R₂ represent an alkyl radical substituted by a carboxyl radicalcan be converted to metal salts or to addition salts with nitrogen basesin a manner analogous to that described above for the acid additionsalts, except that the acid is replaced with a metal hydroxide or anorganic base.

The synergistines obtained by fermentation are used for the treatment ofinfections caused by Gram-positive bacteria (of the generaStaphylococcus, Streptococcus, Pneumococcus or Enterococcus) andGram-negative bacteria (of the genus Haemophilus, Gonococcus orMeningococcus). However, known synergistines have the disadvantage ofbeing insoluble in aqueous media and can therefore only be administeredorally, generally in the form of capsules, coated tablets or ordinarytablets. Because of this insolubility, it is impossible to use the knownsynergistines if the patient is not capable of swallowing; this is thecase, in particular, in paediatrics and intensive care, whereas thespectrum of activity of these products would make them a valuableindication in a large number of circumstances, e.g. in cases of comatosesepticaemia.

The new compounds of the invention have the considerable advantage ofbeing soluble or capable of being solubilized in water, either in theform of parent substances or in the form of salts, at therapeuticallyuseful levels, while at the same time retaining the general spectrum ofantibacterial activity of synergistines. They are especially active invitro against Staphylococcus aureus Smith at concentrations of between 8and 125 μg/ml.

Their toxicity is generally low. Their LD₅₀ is generally greater than500 mg/kg, when administered subcutaneously to mice.

Of particular value are the compounds of the general formula (I) inwhich: Y represents hydrogen or dimethylamino and

R₁ represents hydrogen and R₂ represents hydroxyl, alkyl or alkylsubstituted by hydroxyl or dialkylamino, or R₂ represents piperidinylunsubstituted or substituted by alkyl, or

R₁ represents alkylcarbonyl and R₂ represents dialkylaminoalkyl, or

R₁ and R₂, which are identical or different, represent alkyl or alkylsubstituted by carboxyl or dialkylamino, or together form, with thenitrogen atom to which they are attached, 4-methylpiperazinyl. Amongthese compounds, those which are more especially active are thecompounds of the formula (I) in which: Y represents a dimethylaminoradical and

R₁ represents hydrogen and R₂ represents hydroxyl or alkyl of 1 or 2carbon atoms or alkylpiperidinyl of which the alkyl contains 1 or 2carbon atoms, or

R₁ represents alkyl of 1 or 2 carbon atoms and R₂ represents alkyl ordimethylamino alkyl, or

R₁ and R₂ together form, with the nitrogen atom to which they areattached, alkylpiperazinyl of which the alkyl contains 1 or 2 carbonatoms, and especially the following products:5γ-deoxy-5γ-dimethylaminopristinamycin I_(A),5γ-deoxy-5γ-methylaminopristinamycin I_(A),5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)-N-methylamino]-pristinamycinI_(A), 5γ-deoxy-5γ-(4-methylpiperazin-1-yl)-pristinamycin I_(A) and5γ-deoxy-5γ-hydroxyaminopristinamycin I_(A).

For use in therapy, the compounds of the invention can be employed assuch, i.e. in the form of the base, but for use in aqueous solution,which constitutes the main advantage of the new products it isparticularly advantageous to use their pharmaceutically acceptablesalts, i.e. salts which are non-toxic at the doses used.

Pharmaceutically acceptable salts which may be mentioned are theaddition salts with mineral acids, such as hydrochlorides,hydrobromides, sulphates, nitrates and phosphates, or with organicacids, such as acetates, propionates, succinates, maleates, fumarates,methanesulphonates, p-toluenesulphonates and isethionates, orsubstitution derivatives of these compounds. Other pharmaceuticallyacceptable salts which may be mentioned are the salts with alkalimetals, such as the sodium, potassium and lithium salts, the salts withalkaline earth metals, such as the magnesium salt, the ammonium salt andthe addition salts with organic nitrogen bases such as ethanolamine,diethanolamine, trimethylamine, triethylamine, methylamine, propylamine,diisopropylamine, N,N-dimethylethanolamine, benzylamine, dibenzylamine,dicyclohexylbenzylamine, N-benzyl-β-phenethylamine,N,N'-dibenzylethylenediamine, benzhydrylamine, arginine, leucine, lysineor N-methylglucamine.

The Examples which follow illustrate the invention. The NMR spectra ofthe products described in these Examples have general characteristicswhich are common to all the products and particular characteristicswhich are peculiar to each of the products according to the nature ofthe substituents Y, R₁ and R₂. In Example 1, the assignment of all theprotons in the molecule is given; in the subsequent Examples, only theparticular characteristics due to the variable radicals are mentioned.All the protons are designated according to the numbering indicated inthe general formula (VII) and recommended by J. O. ANTEUNIS et al. [Eur.J. Biochim., 58, 259 (1975)]. ##STR7##

All the spectra were run at 250 MHz in deuterchloroform; the chemicalshifts are expressed in ppm relative to the signal fortetramethylsilane. The abbreviations used below are as follows:

s=singlet

d=doublet

t=triplet

mt=multiplet

up=unresolved peaks

dd=doublet of doublets

dt=doublets of triplets

ddd=doublet of doublet of doublets

dddd=doublet of doublet of doublet of doublets

In Examples 2 to 15, the following are given respectively in brackets:the chemical shift, the shape of the signal, the integration (number ofprotons, if appropriate with the percentage of isomer) and theassignment of the protons.

In the Examples which follow "flash" chromatography is to be understoodas meaning a purification technique which comprises using a shortchromatography column and operating under a moderate pressure (50 kPa)using a silica of particle size 40-63 μm, according to the method of W.C. STILL, M. KAHN and A. MITRA [J. Org. Chem., 43, 2923 (1978)].

EXAMPLE 1

Pristinamycin I_(A) (0.5 g) and sodium cyanoborohydride (20 mg) areadded to a solution of 3-dimethylaminopropylamine (0.41 cc) in methanol(15 cc) containing a 2N methanolic solution of hydrogen chloride (2.4cc), kept at 55° C. The solution obtained is then allowed to return to atemperature of the order of 20° C. for about 2 hours and thenconcentrated to dryness under reduced pressure (2.7 kPa) at 30° C. Theresidue obtained is triturated with a mixture of methylene chloride (50cc) and a saturated aqueous solution of sodium bicarbonate (50 cc); theorganic phase is decanted and the aqueous phase is extracted twice withmethylene chloride (20 cc in total). The organic phases are combined,dried over magnesium sulphate and filtered and the filtrate is thenconcentrated to dryness under reduced pressure (2.7 kPa) at 30° C. Theresidue obtained is purified by "flash" chromatography [eluent:chloroform/methanol (80/20 by volume)]. Fractions 15 to 30 are combinedand concentrated to dryness under reduced pressure (2.7 kPa) at 30° C.;the residue obtained is triturated with ethyl ether (5 cc), filtered offand dried under reduced pressure (0.027 kPa) at 20° C. This gives5γ-deoxy-5γ-(3-dimethylaminopropyl)aminopristinamycin I_(A) (60 mg) inthe form of a cream powder melting at about 160° C.

The complete NMR spectrum has the following characteristics:

    ______________________________________                                        δ(ppm)                                                                            Shape of the signal                                                                           Assignment                                          ______________________________________                                        8.40      d                   6 NH                                            8.25      d                   1 NH                                            7.55      dd                  1'H.sub.6                                       7.05      up                  6γ + 6δ + 6ε                7         dd                  1'H.sub.4                                       6.90      dd                  1'H.sub.5                                       6.70      d                                                                                                 4δ + 4ε                           6.40      d                                                                   6.50      d                   2 NH                                            5.75      ddd                 1β                                         5.45      d                   6α                                        5.25      dd                  4α                                        5         s (broad)           5α                                        4.75      dd                  1α                                        4.60      up                  2α                                        4.45      d (broad)           5ε.sub.1                                4.40      dd                  3α                                        3.4       dd (broad)          3δ.sub.1                                  3.20      dd (broad)          3δ.sub.2                                  3         s                   4 CH.sub.3                                      3         up                  5γ + 4β.sub.1 and 2                  2.80      s                   4 N(CH.sub.3).sub.2                             2.65      t                   --NCH.sub.2 --(chain)                           2.35      up                  5ε.sub.2 + 5β.sub.1                2.25      t                   --NCH.sub.2 --(chain)                           2.20      s                   --N(CH.sub.3 ).sub.2 (chain)                    1.60      up                  --CH.sub.2 --(chain)                                                          2β + 3γ                              1.25      d                   1γ                                        0.90      t                   2γ                                        0.50      dddd                5β.sub.2                                   ______________________________________                                    

A 10% aqueous solution of5γ-deoxy-5γ-(3-dimethylaminopropyl)aminopristinamycin I_(A) (product A)in the form of the hydrochloride is obtained with:

product A . . . 0.1 g

2N hydrochloric acid . . . 0.52 cc

distilled water . . . q.s. 1 cc

EXAMPLE 2

A 5N ethanolic solution of dimethylamine (2.8 cc) and then a 5Nmethanolic solution of hydrogen chloride (2 cc) are added to a solutionof pristinamycin I_(A) (2 g) in methanol (25 cc). Sodiumcyanoborohydride (76 mg) is added to the resulting solution and themixture is then stirred for 48 hours at a temperature of the order of20° C. The reaction mixture is then concentrated to dryness underreduced pressure (2.7 kPa) at 30° C. The residue is triturated with amixture of methylene chloride (25 cc) and a saturated aqueous solutionof sodium bicarbonate (25 cc); the organic phase is decanted and theaqueous phase is extracted twice with methylene chloride (50 cc intotal). The organic phases are combined, dried over magnesium sulphateand filtered and the filtrate is then concentrated to dryness underreduced pressure (2.7 kPa) at 30° C. The residue is purified by "flash"chromatography [eluent: chloroform/methanol (92/8 by volume)] .Fractions 5 to 12 are combined and concentrated to dryness under reducedpressure (2.7 kPa) at 30° C. This gives5γ-deoxy-5γ-dimethylaminopristinamycin I_(A) (0.7 g) in the form of abeige powder melting at about 170° C.

NMR spectrum: 0.70 (dt, 1H: 5β₂); 2.10 to 2.60 (up, 4H: 5δ₁ +5δ₂ +5β₁+5γ); 2.15 (s, 3H×0.8: --N(CH₃)₂ 1st isomer); 2.20 (s, 3H×0.2: --N(CH₃)₂2nd isomer).

A 2% aqueous solution of 5γ-deoxy-5γ-dimethylaminopristinamycin I_(A)(product B) in the form of the hydrochloride is obtained with:

product B . . . 0.05 g

0.1N hydrochloric acid . . . 0.56 cc

distilled water . . . q.s. 2.5 cc

EXAMPLE 3

By following a procedure analogous to that described in Example 2, butstarting from pristinamycin I_(A) (1 g), 7N ethanolic solution ofmethylamine (1 cc) and sodium cyanoborohydride (0.088 g), and after"flash" chromatography [eluent: chloroform/methanol (88/12 by volume)]and concentration to dryness of fractions 11 to 19 under reducedpressure (2.7 kPa) at 30° C., 5γ-deoxy-5γ-methylaminopristinamycin I_(A)(0.35 g) is obtained in the form of a yellow powder melting at about185° C.

NMR spectrum: 0.5 (mt, 1H: 5β₂); 2.4 (mt, 6H: --NHCH₃ +5δ₁ +5δ₂ +5β₁);7.75 (mt, 1H×0.8: 1'H₆ 1st isomer); 7.97 (mt, 1H×0.2: 1'H₆ 2nd isomer).

A 1% aqueous solution of 5γ-deoxy-5γ-methylaminopristinamycin I_(A)(product C) in the form of the hydrochloride is obtained with:

product C . . . 0.05 g

0.1N hydrochloric acid . . . 0.57 cc

distilled water . . . q.s. 5 cc

EXAMPLE 4

By following a procedure analogous to that described in Example 2, butstarting from pristinamycin I_(A) (6 g),(2-dimethylaminoethyl)methylamine (5.4 cc), a 5N methanolic solution ofhydrogen chloride (18 cc) and sodium cyanoborohydride (0.3 g), and afterpurification by "flash" chromatography [eluent: chloroform/methanol(85/15 by volume)] and concentration to dryness of fractions 10 to 17under reduced pressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)-N-methylamino]pristinamycin I_(A)(1.2 g) is obtained in the form of a white powder melting at about 120°C.

NMR spectrum: 0.75 (dt, 1H: 5β₂); 2.15 (s, 3H: >N--CH₃); 2.35 (up, 7H:--N(CH₃)₂ +5β₁); 2.4 to 2.8 (up, 7H: >N--CH₂ --CH₂ --N<+5δ₁ +5δ₂ +5γ);7.75 (mt, 1H: 1'H₆ [only 1 isomer]).

A 10% aqueous solution of5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)-N-methylamino]pristinamycin I_(A)(product D) in the form of the hydrochloride is obtained with:

product D . . . 0.5 g

1N hydrochloric acid . . . 1.05 cc

distilled water . . . q.s. 5 cc

EXAMPLE 5

By following a procedure analogous to that described in Example 1, butstarting from pristinamycin I_(A) (10 g), 2-dimethylaminoethylamine (6.2g) and sodium cyanoborohydride (0.38 g), and after purification by"flash" chromatography [eluent: chloroform/methanol (88/12 by volume)]and concentration to dryness of fractions 16 to 30 under reducedpressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-(2-dimethylaminoethyl)aminopristinamycin I_(A) (1.1 g) isobtained in the form of a yellow powder melting at about 180° C.

NMR spectrum: 0.8 (up, 1H: 5β₂); 2.3 (s, 6H: --N(CH₃)₂); 2.4 to 2.8 (up,8H: >N--CH₂ CH₂ --N<+5β₁ +5γ+5δ₁ +5δ₂); 7.70 (mt, 1H×0.75: 1'H₆ 1stisomer); 7.95 (mt, 1H×0.25: 1'H₆ 2nd isomer).

A 10% solution of 5γ-deoxy-5γ-(2-dimethylaminoethyl)aminopristinamycinI_(A) (product E) in the form of the hydrochloride is obtained with:

product E . . . 0.1 g

0.2N hydrochloric acid . . . 0.53 cc

distilled water . . . q.s. 1 cc

EXAMPLE 6

A 3 Å molecular sieve (5 g) is added to a solution of pristinamycinI_(A) (3 g), 4-diethylamino-1-methylbutylamine (3.3 g), sodiumcyanoborohydride (0.11 g) and a 5N methanolic solution of hydrogenchloride (9 cc) in methanol (75 cc). The suspension obtained is stirredfor 4 days at a temperature of the order of 20° C. and then filtered;the filtrate is concentrated to dryness under reduced pressure (2.7 kPa)at 30° C. The residue is triturated with a mixture of methylene chloride(50 cc) and a saturated aqueous solution of sodium bicarbonate (50 cc);the organic phase is decanted and the aqueous phase is extracted twicewith methylene chloride (50 cc in total). The organic phases arecombined, dried over magnesium sulphate and filtered and the filtrate isthen concentrated to dryness under reduced pressure (2.7 kPa) at 30° C.The residue is purified by "flash" chromatography [eluent:chloroform/methanol (90/10 by volume)]. This gives5γ-deoxy-5γ-(4-diethylamino-1-methylbutyl)aminopristinamycin I_(A) (0.7g) in the form of a beige powder melting at about 160° C.

NMR spectrum: 1.10 (mt, 9H: --N(CH₂ CH₃)₂ + ##STR8## about 1.7 (up, 4H:--CH₂ --CH₂ --CH₂ --N(C₂ H₅)₂); 2.90 (up, 6H: --CH₂ N(CH₂ CH₃)₂); 7.70(mt, 1H×0.45: 1'H₆ 1st isomer); 7.77 (mt, 1H×0.55: 1'H₆ 2nd isomer).

A 10% aqueous solution of5γ-deoxy-5γ-(4-diethylamino-1-methylbutyl)aminopristinamycin I_(A)(product F) in the form of the hydrochloride is obtained with:

product F . . . 0.1 g

0.1N hydrochloric acid . . . q.s. 1 cc

EXAMPLE 7

By following a procedure analogous to that described in Example 1, butstarting from pristinamycin I_(A) (4 g), N-methylpiperazine (2.7 g) andsodium cyanoborohydride (0.16 g), and after purification by "flash"chromatography [eluent: chloroform/methanol (95/5 by volume)] andconcentration to dryness of fractions 12 to 23 under reduced pressure(2.7 kPa) at 30° C., 5γ-deoxy-5γ-(4-methylpiperazin-1-yl)pristinamycinI_(A) (0.7 g) is obtained in the form of a white powder melting at about195° C.

NMR spectrum: 0.8 (up, 1H: 5β₂); 2.05 to 2.30 (up, 3H: 5δ₁ +5δ₂ +5γ);2.30 (s, 3H: >N--CH₃); 2.50 (up, 9H: ##STR9## +5β₁); 7.70 (mt, 1H×0.9:1'H₆ 1st isomer); 7.98 (mt, 1H×0.1: 1'H₆ 2nd isomer).

A 10% aqueous solution of5γ-deoxy-5γ-(4-methylpiperazin-1-yl)pristinamycin I_(A) (product G) inthe form of the hydrochloride is obtained with:

product G . . . 0.1 g

0.2N hydrochloric acid . . . 0.52 cc

distilled water . . . q.s. 1 cc

EXAMPLE 8

By following a procedure analogous to that described in Example 1, butstarting from pristinamycin I_(A) (6.0 g), sodium cyanoborohydride (0.24g) and 4-amino-1-methylpiperidine (4.65 g), and after purification by"flash" chromatography [eluent: chloroform/methanol (80/20 by volume)]and concentration to dryness of fractions 12 to 36 under reducedpressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-(1-methylpiperidin-4-ylamino)pristinamycin I_(A) (1.75 g) isobtained in the form of a beige powder melting at about 195° C.

NMR spectrum: 0.25 (ddd, 1H: 5β₂); 2.3 (up, 3H: >N--CH₃); 2.40 (d, 1H:5ε); 3 (up, 4H: ##STR10## 5.10 (s, 1H: 5α); 7.75 (dd, 1H×0.8: 1'H₆ 1stisomer); 8 (dd, 1H×0.2: 1'H₆ 2nd isomer).

A 3.7% aqueous solution of5γ-deoxy-5γ-(1-methylpiperidin-4-ylamino)pristinamycin I_(A) (product H)in the form of the hydrochloride is obtained with:

product H . . . 0.03 g

0.1N hydrochloric acid . . . 0.8 cc

The 4-amino-1-methylpiperidine can be prepared according to the methoddescribed by E. F. Elslager et al., J. Med. Chem., 17, 99 (1974).

EXAMPLE 9

By following a procedure analogous to that described in Example 1, butstarting from pristinamycin I_(A) (2 g), hydroxylamine hydrochloride(0.97 g) and sodium cyanoborohydride (0.076 g), and after purificationby "flash" chromatography [eluent: chloroform/methanol (95/5 by volume)]and concentration to dryness of fractions 10 to 17 under reducedpressure (2.7 kPa) at 30° C., 5γ-deoxy-5γ-hydroxyaminopristinamycinI_(A) (1.1 g) is obtained in the form of a white powder melting at about170° C.

NMR spectrum: 0.4 (up, 1H: 5β₂); 2.45 (d, 1H: 5β₂); 3.1 (d: 5γ incomplex unresolved peaks); 7.80 (mt, 1H×0.75: 1'H₆ 1st isomer); 7.95(mt, 1H×0.25: 1'H₆ 2nd isomer)

A 10% aqueous solution of 5γ-deoxy-5γ-hydroxyaminopristinamycin I_(A)(product I) in the form of the hydrochloride is obtained with:

product I . . . 0.1 g

0.2N hydrochloric acid . . . 0.57 cc

distilled water . . . q.s. 1 cc

EXAMPLE 10

Sodium cyanoborohydride (0.7 g) is added to a solution of5γ-deoxy-5γ-hydroxyiminopristinamycin I_(A) (12.5 g) in methanol (300cc) containing a 2N methanolic solution of hydrogen chloride (10 cc).The solution obtained is stirred for 2 days at a temperature of theorder of 20° C. and then concentrated to dryness under reduced pressure(2.7 kPa) at 30° C. The residue is triturated in a mixture of methylenechloride (200 cc) and a saturated aqueous solution of sodium bicarbonate(100 cc); the organic phase is decanted and the aqueous phase isextracted with methylene chloride (100 cc). The organic phases arecombined, dried over magnesium sulphate and filtered and the filtrate isconcentrated to dryness under reduced pressure (2.7 kPa) at 30° C. Afterpurification by "flash" chromatography [eluent: chloroform/methanol(95/5 by volume)], 5γ-deoxy-5γ-hydroxyaminopristinamycin I_(A) (6.8 g)is obtained in the form of a white powder melting at about 170° C.

The NMR spectrum is identical to that obtained from the product preparedin Example 9.

The 5β-deoxy-5γ-hydroxyiminopristinamycin I_(A) can be obtained bystirring a solution of pristinamycin I_(A) (15 g) and hydroxylaminehydrochloride (7.5 g) in methanol (150 cc) containing a 2N methanolicsolution of hydrogen chloride (8 cc), for 5 hours, at a temperature ofthe order of 20° C. The reaction mixture is then concentrated to drynessunder reduced pressure (2.7 kPa) at 30° C. The residue is trituratedwith a mixture of chloroform (100 cc) and a saturated aqueous solutionof sodium bicarbonate (100 cc); the organic phase is decanted and theaqueous phase is extracted twice with chloroform (200 cc in total). Theorganic phases are combined, dried over magnesium sulphate and filteredand the filtrate is concentrated to dryness under reduced pressure (2.7kPa) at 30° C. This gives 5γ-deoxy-5γ-hydroxyiminopristinamycin I_(A)(14 g) in the form of a beige powder melting at 210° C.

NMR spectrum: 0.35 (dd, 1H: 5β₂); 3.25 (up, 2H: 4ε₂ +5β₁); 5.05 (d, 1H:5α); 5.5 (up, 2H including 5ε₁); 7.80 (dd, 1H×0.40: 1'H₆ 1st isomer);7.90 (dd, 1H×0.60: 1'H₆ 2nd isomer).

EXAMPLE 11

By following a procedure analogous to that described in Example 1, butstarting from pristinamycin I_(A) (4 g), 3-aminopropan-1-ol (3 g) andsodium cyanoborohydride (0.16 g), and after purification by "flash"chromatography [eluent: chloroform/methanol (90/10 by volume)] andconcentration to dryness of fractions 9 to 16 under reduced pressure(2.7 kPa) at 30° C., 5γ-deoxy-5γ-(3-hydroxypropyl)aminopristinamycinI_(A) (1.1 g) is obtained in the form of a cream powder melting at about160° C.

NMR spectrum: 0.45 (up, 1H: 5β₂); 1.70 (up, 2H: --CH₂ --CH₂ --CH₂ --);2.0 (up, 1H: 5δ); 2.40 (up, 2H: 5δ+5β₁); 2.90 (up, 2H: --NH--CH₂ --);3.30 (up: 5γ); 3.75 (t, 2H: --CH₂ --OH); 7.80 (mt, 1H×0.9: 1'H₆ 1stisomer); 7.95 (mt, 1H×0.1: 1'H₆ 2nd isomer).

A 2% aqueous solution of 5γ-deoxy-5γ-(3-hydroxypropyl)aminopristinamycinI_(A) (product J) in the form of the hydrochloride is obtained with:

product J . . . 0.1 g

0.1N hydrochloric acid . . . 1.08 cc

distilled water . . . q.s. 5 cc

EXAMPLE 12

By following a procedure analogous to that described in Example 6, butstarting from pristinamycin I_(A) (4 g), N-methylaminoacetic acid (2.5g) and sodium cyanoborohydride (0.076 g), and after purification by"flash" chromatography [eluent: chloroform/methanol (80/20 by volume)]and concentration to dryness of fractions 6 to 12 under reduced pressure(2.7 kPa) at 30° C.,5γ-[N-(carboxymethyl)methylamino]-5γ-deoxypristinamycin I_(A) (0.8 g) isobtained in the form of a cream powder melting at about 140° C.

NMR spectrum: 1.15 (up, 1H: 5β₂); 2.2 (up, 2H: 5δ₁ +5δ₂) 2.40 (up, 4H:>N--CH₃ +5β₁); 2.8 (up: 5γ); 3.5 (up, 2H: >N--CH₂ CO₂ H); 8.0 (mt, 1H:1'H₆).

A 2% aqueous solution of5γ-[N-(carboxymethyl)-methylamino]-5γ-deoxypristinamycin I_(A) (productK) is obtained with:

product K . . . 0.2 g

distilled water . . . q.s. 10 cc

EXAMPLE 13

Acetyl chloride (0.3 cc) is added to a solution of5γ-deoxy-5γ-(2-dimethylaminoethyl)aminopristinamycin I_(A) (3.2 g) inchloroform (50 cc) containing triethylamine (0.6 cc). The reactionmixture is stirred for 30 minutes at a temperature of the order of 20°C. and then concentrated to dryness under reduced pressure (2.7 kPa) at30° C. The residue is purified by "flash" chromatography [eluent:chloroform/methanol (90/10 by volume)]; by concentration to dryness offractions 10 to 21 under reduced pressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)-acetamido]pristinamycin I_(A) (1.8g) is obtained in the form of a white powder melting at about 170° C.

NMR spectrum: 0.9 (up, 4H: 2γ+5β₂); 2.05 to 2.15 (up, 3H: 5δ₁ +5δ₂ +5γ);2.15 (s, 3H: --COCH₃); 2.45 (s, 6H: --N(CH₃)₂); 2.35 to 2.60 (up, 5H:>N--CH₂ --CH₂ --N<+5β₁); 7.8 (mt, 1H×0.75: 1'H₆ 1st isomer); 8.25 (mt,1H×0.25: 1'H₆ 2nd isomer).

A 10% aqueous solution of5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)acetamido]pristinamycin I_(A)(product L) in the form of the hydrochloride is obtained with:

product L . . . 0.1 g

0.2N hydrochloric acid . . . 0.51 cc

distilled water . . . q.s. 1 cc

The 5γ-deoxy-5γ-(2-dimethylaminoethyl)aminopristinamycin I_(A) can beprepared as described in Example 5.

EXAMPLE 14

By following a procedure analogous to that described in Example 13, butstarting from 5γ-deoxy-5γ-(3-dimethylaminopropyl)aminopristinamycinI_(A) (2.4 g) and acetyl chloride (0.2 cc), and after purification by"flash" chromatography [eluent: chloroform/methanol (90/10 by volume)]and concentration to dryness of fractions 13 to 18 under reducedpressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-[N-(3-dimethylaminopropyl)acetamido]pyristinamycin I_(A)(1.6 g) is obtained in the form of an ochre powder melting at 210° C.

NMR spectrum: 0.8 (up, 1H: 5β₂); 1.4 (up, 2H: --CH₂ CH₂ --CH₂ --); 2.20(s: --COCH₃ 1st isomer); 2.40 (s: --COCH₃ 2nd isomer); 2.6 (s, 6H:--N(CH₃)₂); 2.4 to 2.6 (up, 1H: 5γ); 2.9 (up, 2H: --CH₂ N<); 7.8 (mt,1H×0.9: 1'H₆ 1st isomer); 8.0 (mt, 1H×0.1: 1'H₆ 2nd isomer).

A 10% aqueous solution of5γ-deoxy-5γ-[N-(3-dimethylaminopropyl)acetamido]pristinamycin I_(A)(product M) in the form of the hydrochloride is obtained with:

product M . . . 0.1 g

0.2N hydrochloric acid . . . 0.5 cc

distilled water . . . q.s. 1 cc

The 5γ-deoxy-5γ-(3-dimethylaminopropyl)aminopristinamycin I_(A) can beprepared as described in Example 1.

EXAMPLE 15

By following a procedure analogous to that described in Example 1, butstarting from virginiamycin S (2.5 g) and sodium cyanoborohydride (0.1g), and after purification by "flash" chromatography [eluent:chloroform/methanol (90/10 by volume)] and concentration to dryness offractions 8 to 15 under reduced pressure (2.7 kPa) at 30° C.,5γ-deoxy-5γ-(3-dimethylaminopropyl)aminovirginiamycin S (0.17 g) isobtained in the form of a beige powder melting at about 140° C.

NMR spectrum: 0.6 (ddd, 1H: 5β₂); 1.65 (up, 2H: --NHCH₂ --CH₂ --CH₂ N<);2.25 (s, 6H: ##STR11## 2.35 and 2.70 (up, 4H: --NH--CH₂ --CH₂ CH₂ --N<);3.20 (d, 1H: 5ε₂); 5.20 (up, 1H: 5α); 7.70 (dd, 1H: 1'H₆).

A 10% aqueous soluton of5γ-deoxy-5γ-(3-dimethylaminopropyl)aminovirginiamycin S (product N) inthe form of the hydrochloride is obtained with:

product N . . . 10 mg

0.2N hydrochloric acid . . . 0.055 cc

distilled water . . . q.s. 0.1 cc

The present invention includes within its scope pharmaceuticalcompositions comprising a compound of formula (I), in the free form orin the form of an addition salt with a pharmaceutically acceptable acidor, if appropriate, a pharmaceutically acceptable base, in associationwith one or more pharmaceutically acceptable diluents or adjuvants. Thecompositions may also contain other pharmaceutically compatible product,which may be inert or physiologically active. The drugs according to theinvention can be administered parenterally, rectally, orally ortopically.

The sterile compositions for parenteral administration can preferably besuspensions, emulsions or aqueous or non-aqueous solutions. Water,propylene glycol, polyethylene glycol, vegetable oils, in particularolive oil, injectable organic esters, e.g. ethyl oleate, or othersuitable organic solvents can be employed as the solvent or vehicle.These compositions can also contain adjuvants, in particular wettingagents, agents for imparting isotonicity, emulsifiers, dispersants andstabilizers. Sterilization can be carried out in several ways, e.g. byfiltration under aseptic conditions, by incorporating sterilizing agentsinto the composition, by irradiation or by heating. The compositions canalso be prepared in the form of sterile solid compositions which can bedissolved in an injectable sterile medium at the time of use.

The compositions for rectal administration are suppositories or rectalcapsules, which contain, in addition to the active principle, excipientssuch as cocoa butter, semi-synthetic glycerides or polyethylene glycols.

Tablets, pills, powders or granules can be used as solid compositionsfor oral administration. In these compositions, the active productaccording to the invention (if appropriate in association with anotherpharmaceutically compatible product) is mixed with one or more inertdiluents or adjuvants such as sucrose, lactose or starch. Thesecompositions can also comprise substances other than diluents, e.g. alubricant such as magnesium stearate.

Solutions, suspensions, syrups and elixirs containing inert diluentssuch as water or paraffin oil, and pharmaceutically acceptableemulsions, can be used as liquid compositions for oral administration.These compositions can also comprise substances other than diluents,e.g. wetting, sweetening or flavouring products.

The compositions for topical administration can be e.g. creams,ointments, lotions, eye lotions, mouthwashes, nose drops or aerosols.

The invention includes within its scope a method of killing orinhibiting the growth of bacteria, e.g. those mentioned above, whichcomprises exposing said bacteria to contact with an effectivebactericidal or bacteriostatic concentration of a compound of formula(I) (or salt thereof).

In human therapy, the compounds of the invention are particularly usefulin the treatment of infections of bacterial origin. The dose useddepends on the desired effect and the duration of the treatment. For anadult, the dose is generally between 2000 and 4000 mg per day,administered parenterally in particular intravenously by slow perfusion,administered normally while symptoms of infection persist. In general,the physician will determine the dosage which he considers to be mostappropriate as a function of the age, the weight and all the otherfactors peculiar to the subject to be treated.

The Examples which follow illustrate compositions according to theinvention.

EXAMPLE A

An injectable solution for perfusion is prepared which contains 10g/liter of active product and has the following composition:

5γ-deoxy-5γ-dimethylaminopristinamycin I_(A) : 10 g

0.1N aqueous solution of hydrochloric acid: 110 cc

distilled water q.s.: 1000 cc.

EXAMPLE B

An injectable solution for perfusion is prepared which contains 5g/liter of active product and has the following composition:

5γ-deoxy-5γ-methylaminopristinamycin I_(A) : 5 g

0.1N aqueous solution of hydrochloric acid: 57 cc

distilled water q.s.: 1000 cc

We claim:
 1. A synergistine of the formula: ##STR12## in which Y ishydrogen or dimethylamino; and (I) R₁ is hydrogen and R₂ is(i) hydroxyl,(ii) alkyl, (iii) alkyl substituted by carboxyl, alkoxycarbonyl,hydroxyl, alkylamino, dialkylamino, or dialkylamino in which the alkylsform, with the nitrogen atom to which they are attached, a 4-membered to7-membered heterocycle chosen from azetidinyl, pyrrolidinyl,piperidinyl, piperazinyl, N-alkylpiperazinyl and azepinyl, (iv)cycloalkyl of 3 to 7 carbon atoms, or (v) a saturated 4-membered to7-membered heterocycle chosen from azetidinyl, pyrrolidinyl, piperidinyland azepinyl, these heterocycles being unsubstituted or substituted onthe nitrogen atom by alkyl; or (II) R₁ is formyl or alkylcarbonyl and R₂is(i) alkyl substituted by carboxyl, (ii) alkylamino, (iii)dialkylamino, (iv) dialkylamino in which the alkyls form, with thenitrogen atom to which they are attached, a 4-membered to 7-memberedheterocycle chosen from azetidinyl, pyrrolidinyl, piperidinyl,piperazinyl, N-alkylpiperazinyl and azepinyl, or (v) a saturated4-membered to 7-membered heterocycle chosen from azetidinyl,pyrrolidinyl, piperidinyl and azepinyl, these heterocycles beingunsubstituted or substituted on the nitrogen atom by alkyl; or (III) R₁and R₂, which are identical or different, are each alkyl which isunsubstituted or substituted by carboxyl, alkoxycarbonyl, hydroxyl,alkylamino, dialkylamino, or dialkylamino in which the alkyls form, withthe nitrogen atom to which they are attached, a 4-membered to 7-memberedheterocycle chosen from azetidinyl, pyrrolidinyl, piperidinyl,piperazinyl, N-alkylpiperazinyl and azepinyl, or (IV) R₁ and R₂ togetherform, with the nitrogen atom to which they are bonded, a 4-membered to7-membered heterocycle chosen from azetidinyl, pyrrolidinyl,piperidinyl, morpholinyl, piperazinyl, and piperazinyl substituted byalkyl; all the aforesaid alkyl radicals and alkyl portions of radicalscontaining 1 to 5 carbon atoms each in a linear or branched chain; andits pharmaceutically acceptable salts.
 2. A synergistine according toclaim 1 in which Y represents hydrogen or dimethylamino and(I) R₁represents hydrogen and R₂ represents(i) hydroxyl, (ii) alkyl, (iii)alkyl substituted by hydroxyl or dialkylamino, or (iv) piperidinylunsubstituted or substituted by alkyl, or (II) R₁ representsalkylcarbonyl and R₂ represents dialkylaminoalkyl, or (III) R₁ and R₂,which are identical or different, are each alkyl which is unsubstitutedor substituted by carboxyl or dialkylamino, or (IV) R₁ and R₂ togetherform, with the nitrogen atom to which they are attached,4-methylpiperazinyl, and its pharmaceutically acceptable salts.
 3. Asynergistine according to claim 1 in which Y represents a dimethylaminoand(I) R₁ represents hydrogen and R₂ represents hydroxyl, alkyl of 1 or2 carbon atoms, or alkylpiperidinyl of which the alkyl contains 1 or 2carbon atoms, or (II) R₁ represents alkyl of 1 or 2 carbon atoms and R₂represents alkyl or dimethylaminoalkyl, or (III) R₁ and R₂ togetherform, with the nitrogen atom to which they are attached,alkylpiperazinyl in which the alkyl contains 1 or 2 carbon atoms, andits pharmaceutically acceptable salts.
 4. A synergistine according toclaim 1 which is 5γ-deoxy-5γ-dimethylaminopristinamycin I_(A) and itspharmaceutically acceptable salts.
 5. A synergistine according to claim1 which is 5γ-deoxy-5γ-methylaminopristinamycin I_(A) and itspharmaceutically acceptable salts.
 6. A synergistine according to claim1 which is5γ-deoxy-5γ-[N-(2-dimethylaminoethyl)-N-methylamino]pristinamycin I_(A)and its pharmaceutically acceptable salts.
 7. A synergistine accordingto claim 1 which is 5γ-deoxy-5γ-(4-methyl-piperazin-1-yl)-pristinamycinI_(A) and its pharmaceutically acceptable salts.
 8. A synergistineaccording to claim 1 which is 5γ-deoxy-5γ-hydroxyaminopristinamycinI_(A) and its pharmaceutically acceptable salts.
 9. A pharmaceuticalcomposition useful as an antibacterial agent which contains an effectiveantibacterial amount of a synergistine according to claim 1, or apharmaceutically acceptable salt thereof in association with one or morepharmaceutically compatible diluents or adjuvants.
 10. A pharmaceuticalcomposition according to claim 9 in the form of a sterile injectablesolution of a pharmaceutically acceptable salt of a said synergistine.11. A method of killing or inhibiting the growth of bacteria in a hostin which antibacterial therapy is required which comprises exposing saidbacteria to contact with an effective amount of a synergistine asclaimed in claim 1 or a pharmaceutically acceptable salt thereof.